Final Answer:
Part A: Order Quantity to Maximize Dan's Expected Profit
Optimal Order Quantity Q:
![\[ Q = 100 + Z \cdot 42 \]](https://img.qammunity.org/2024/formulas/business/college/lr40c7yt6b6ianc0bf0z2qjl9f8x03u8a3.png)

Part B: Publisher's Expected Profit
Publisher's Expected Profit:
![\[ \text{Publisher's Profit} = (\$28.00 - \$20.00 - \$7.50) \cdot \text{Expected Demand} \]](https://img.qammunity.org/2024/formulas/business/college/afd8gxuifkv9d7ovisas0kho0uwna50dr1.png)
Part C: Buy-Back Offer
Optimal Order Quantity with Buy-Back Offer
:
![\[ Q_{\text{buyback}} = 100 + Z \cdot 42 \]](https://img.qammunity.org/2024/formulas/business/college/xt3ohld5gvywjohn63v6nxilard9a78eh4.png)
(Using the same formula as Part A)
Total Cost to Dan:
![\[ \text{Total Cost to Dan} = Q_{\text{buyback}} \cdot (\$20.00 + \$1.00) \]](https://img.qammunity.org/2024/formulas/business/college/36omijri1ksknctbolosv5t02gyhz10fa0.png)
Part D: Optimal Buy-Back Price for Maximum Supply Chain Profit
Supply Chain Profit
:
![\[ P_{\text{supply chain}} = \text{Dan's Profit} + \text{Publisher's Profit} \]](https://img.qammunity.org/2024/formulas/business/college/z05fwhf5hovmqtvlrezuycfzoyej9t6elh.png)
Optimal Buy-Back Price:
![\[ \text{Optimal Buy-Back Price} = \$20.00 + \text{Publisher's Average Profit on Returns} \]](https://img.qammunity.org/2024/formulas/business/college/desrsi7gqu0rpkyb79h300m83kyyjq6shp.png)
Step-by-step explanation:
Part A.
The optimal order quantity considers the trade-off between lost sales and holding costs. By using the normal distribution and the desired service level, Dan can determine the order quantity that maximizes expected profit.
Paet B.
The publisher's profit is the difference between the selling price to Dan and the variable cost per book, multiplied by the expected demand.
Part C.
The buy-back offer introduces the cost of shipping unsold copies back to the publisher, affecting the total cost to Dan.
Part D.
Maximizing the supply chain profit involves finding the buy-back price that balances Dan's and the publisher's profits.